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Hello, I am trying the *`Regression &amp; Exploration`* flow of openlane following the <https://openlane.readthedocs.io/en/latest/usage/exploration_script.html|doc>. I wrote a config.tcl like this as a basic configuration:
```# Design
set ::env(DESIGN_NAME) "Rift2LinkA"
set ::env(VERILOG_FILES) "$::env(DESIGN_DIR)/src/*.v"
set ::env(CLOCK_PORT) "clock"
set ::env(CLOCK_NET) "clock"
set ::env(CLOCK_PERIOD) 20
set ::env(FP_SIZING) relative
# set ::env(FP_CORE_UTIL) 20
set ::env(FP_ASPECT_RATIO) 1.2
# set ::env(PL_TARGET_DENSITY) 0.21
set ::env(CELL_PAD) 6
set ::env(RT_MAX_LAYER) {met4}
set ::env(ROUTING_CORES) 16
set ::env(DESIGN_IS_CORE) 0```
And I wrote a regression.config like this:
```FP_CORE_UTIL=(15,17,20)
FP_ASPECT_RATIO=(1.2)
PL_TARGET_DENSITY=(FP_CORE_UTIL*0.01+0.01)```
When I use `python3 run_designs.py --regression ./designs/Rift2LinkA/regression.config -j16  Rift2LinkA` , I found that all three flows running under the basic configuration. The regression configuration didn't take effect. `$PWD/runs/config_regression_1/config.tcl` was generated from basic configuration, although 3 regression configuration files has been generated at `$PWD/` .

Then I reviewed `run_designs.py` and add 2 lines, for `-config_file` , into the codes. And then it looks fine.
```    def run_design(designs_queue):
        nonlocal design_failure_flag, flow_failure_flag
        while not designs_queue.empty():
            design, config, tag, design_name = designs_queue.get(
                timeout=3
            )  # 3s timeout
            run_path = utils.get_run_path(design=design, tag=tag)
            update("START", design)
            command = [
                os.getenv("OPENLANE_ENTRY") or "./flow.tcl",
                "-design",
                design,
                "-tag",
                tag,
                "-config_tag",
                config,
                "-config_file",
                "./designs/"+design+"/"+config+".tcl",
                "-overwrite",
                "-no_save",
                "-run_hooks",
            ] + (["-verbose", "1"] if show_log_output else [])```
Now I want to know if it is a bug or I have done somethings wrong?